Deisseroth, Hegemann and Nagel share the 2026 medicine Nobel for optogenetics

The Nobel Assembly at Karolinska Institutet awarded the 2026 Nobel Prize in Physiology or Medicine on Monday to Karl Deisseroth, Peter Hegemann and Georg Nagel for discoveries concerning light-gated ion channels and optogenetics. The prize is 12 million Swedish kronor, about $1.2 million at the 10.0569 kronor-to-the-dollar rate cited by Reuters, and it is shared equally.

Deisseroth, born in 1971, is the D.H. Chen Professor of Bioengineering and of Psychiatry and Behavioral Sciences at Stanford University, and an investigator at the Howard Hughes Medical Institute. He took a Ph.D. from Stanford in 1998 and an M.D. there in 2000. Hegemann, born in 1954, is Hertie Senior Professor of Neuroscience at Humboldt University of Berlin. He completed his doctorate in 1984 at the Max Planck Institute for Biochemistry in Martinsried, where the prize-cited work was done. Nagel, born in 1953, is professor of molecular plant physiology at the University of Würzburg. He received his Ph.D. from the University of Frankfurt in 1988, and did the cited work at the Max Planck Institute for Biophysics in Frankfurt.

A protein that opens in light

The citation is narrow on purpose. It does not award a therapy. It awards a method that lets a laboratory switch individual nerve cells on or off with light in a living brain.

The method starts with a protein. In the early 2000s Hegemann and Nagel identified channelrhodopsin in the single-celled green alga Chlamydomonas. The protein sits in a membrane and opens a pore when light of the right wavelength hits it. Ions move. The cell's electrical state changes. The pair then showed that the protein did not need the rest of the alga. Put the gene into another cell, and that cell became sensitive to light.

In 2005 Deisseroth published the step that moved the protein from algae and cultured cells into nerve cells taken from rats. A flash of light could trigger a nerve signal. In 2007 he made the same switch work inside the brains of living mice. From that point a researcher could pick a class of neurons, give them the gene, and drive or silence them while the animal was awake.

Per Svenningsson, chair of the Nobel Committee for Physiology or Medicine, said optogenetics provides opportunities for mapping the brain in a way that once could only be dreamed of. The committee's public note says the method is now used in laboratories around the world to show how nerve cells shape memories, feelings and behaviour, and that clinical groups are testing related approaches in attempts to restore sight.

Why a lab can ask a sharper question

The practical distinction from older brain tools is resolution. An electrode can stimulate a region. A drug can bathe a circuit. Optogenetics can, in a prepared animal, address cells that share a genetic marker and leave neighbouring cells of a different type alone. That is why the technique spread through memory research, fear circuits, appetite, movement disorders and sleep. A lab can ask whether a named population is necessary for a behaviour by silencing it, and whether it is sufficient by turning it on.

The prize also marks a route that did not begin in a hospital. Channelrhodopsin was a plant-physiology problem: how a swimming alga finds light. Nagel's current chair is in molecular plant physiology. The medical use arrived after the gene was moved across kingdoms. That path is one reason the assembly could award the medicine prize to a plant biophysicist, a neuroscientist in Berlin, and a psychiatrist-bioengineer in California for the same chain of work.

Deisseroth has spent two decades building the method into a standard kit: better channel variants, fibre optics, viral delivery, and later tools that read activity as well as drive it. The prize text stays with the founding moves, the discovery of the light-gated channel and the demonstration that it can control nerve cells, including in a living brain.

What the citation does not claim

One limit is easy to miss. The award is for a research method and for the channel that made it possible. It is not a claim that optogenetic therapy is established care. The committee notes attempts to restore sight. It does not list an approved treatment or a patient count. Laboratories use the tool every week. Clinics are still at the edge of it.

The money and the calendar are fixed. The physiology or medicine prize opens Nobel week. Physics is due on Tuesday 6 October at the earliest from 11:45 CEST, chemistry on Wednesday, literature on Thursday, peace on Friday from Oslo, and the economic sciences prize on Monday 12 October. The medicine announcement was set for 11:30 CEST at the earliest on Monday. Reuters reported the decision from Stockholm on Monday morning.

The next announcements will test whether this year's prizes stay with tools and mechanisms or move to applied work. For medicine, the assembly has chosen the switch itself: a protein from an alga, a gene moved into a neuron, and a pulse of light that can start or stop a signal the animal would otherwise have made on its own.